I found a little bit for you Eileen :
Ipomoea Iposun Black Tone
Sweet potato. Decorative hanging plant with beautiful black leaf. Ideal for use in mixed dishes or hanging baskets. However, a particularly elegant bedding plant. Plant is on potato-like edible flights which are good. Sun and shade.

Use in hanging baskets, beds, borders and window boxes
Growing Tips
In fall before first frost, dig, dry and store tubers in a dry medium (vermiculite or peat) in a cool dry corner of the basement. When tubers sprout in spring, cut them into sections (at least one eye per section) and plant the sections outdoors after last frost date. Tubers can also be sunk ½ way into a large-mouthed glass jar of water in early spring to generate sprouts that can be removed and planted. Container plants and or rooted cuttings taken in late summer may be overwintered indoors in bright sunny locations.

Potatoes formed by ornamental sweet potato vines are edible but are not as flavorful as those selected as a food crop.

I have these in a hanging basket, Eileen. Grammazoo is spot on. i relate this to "Black-eyed susan" or "Morning glory". I have other ones called "Blacky". Bought them as plug plants back in march from a local garden centre. I'm treating them as annuals. Thought the dark colour would fit in well with our garden theme. :-)